First was a written exam in the morning with many other applicants tackling general knowledge, abstract reasoning, business language / vocabulary, and psychological/behavioral. From this group, the highest scorers are invited for a technical exam in the afternoon, dealing with college-level mathematics and chemical engineering. Weeks later, this was followed by a call from HR telling me that I'd be receiving an email shortly, containing two questions. I was asked to make an essay answering each and send those back within 30 minutes. The final stage was a panel interview, with the HR manager, a scribe, and three employees who were high-ranking personnel in the engineering team. There were eight main questions, to which the panel made various follow-ups (mainly the HR). One was not allowed to answer no / none / I cannot think of any situation / N/A to any of the questions - you were always required to have an answer.